Over the past couple of months, my home computer has been acting up. During bootup the computer start sequence would fail, right after the drive started to spin up. I found that if I turned off the "hard" on/off switch at the back of the computer (the one that's on the power supply), and turned it back on, I could get the computer to start, and it would run without problems. The problem seemed to me to be a power supply that was failing, so I figured that I would need to replace it shortly.

The first time I noticed any problems was when I tried to restart the computer after it had been put in stand-by mode, so I stopped using stand-by and would shut it down instead. Recently, I have started noticing the problem during bootup.

Yesterday morning, I was unable to get the computer to start up, even after three or four attempts using the trick that had worked before. On the way to work I bought a new power supply, and when I got home, installed it. The computer now seems to be working as it should. This leads me to believe that the old power supply actually was the culprit.

I should add that the computer is about two years old, and is one that I put together from parts purchased at a chain computer/electronics store (Fry's). The old power supply was 350 W, which I believe was sufficient for the machine. The new one is 500 W (the place I got it had only one model).

My question is: What would have caused my old power supply to fail after what seems a relatively short time (about two years). The MTBF for the new one is 50,000 hours, which at the rate my wife and I use this computer should last us 50 to 100 years. I don't know anything about the internals of a power supply. What are the parts that can fail?
Thanks,
Mark

About every three to six months, you should open up the case, and blow out the dust using dry compressed air, or those cans of compressed air you can buy at office supply stores. Don't allow the fans to be spun at high speed by the compressed air, as that can cause early bearing failure. However, try to get them as clean as possible. Use a wooden stick to keep them stationary while you're blowing on them.

About every three to six months, you should open up the case, and blow out the dust using dry compressed air, or those cans of compressed air you can buy at office supply stores. Don't allow the fans to be spun at high speed by the compressed air, as that can cause early bearing failure. However, try to get them as clean as possible. Use a wooden stick to keep them stationary while you're blowing on them.

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Not just bearing failure, the counter EMF generated by the moving blade can blow the solid state electronics inside the fan. Been there, done that. It's a reliable way to take out a fan, so Wookie's advice is excellent.

Long time ago my Dad's computer started making noise, it was the power supply fan. I asked him to stop using it the moment it became quiet. Instead he kept on using it, burning out the motherboard, the hard drive, the hard drive interface (blew about 4 of those because the hard drive was bad, but looked good for all of a minute, until the interface card blew), and of course, the power supply. I asked him why he did this (after basically building a new computer from scratch), the answer was, "I thought it fixed itself.". DOH!

Power supplies are cheap, compared to the rest of the computer. Having said that, if the fan is the only problem I won't hesitate to only replace it (NOT for amateurs).

Is the power supply full of dust or other debris? Is the computer in a cabinet with little or no air circulation?

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I didn't open up the power supply, so don't know if it was full of dust. There was a small amount of dust on the fan blade itself, but very little inside the computer case. The computer is not in a cabinet, and there is nothing to block air intake to the fans.

It has the isolation part,,, just check first the two IC there,, if it does not recieve supply from the primary, then it will not give output,,,, check for blotted capacitors,, it causes the output to drop or rise depending on the condition of the system.

Hi
All the above are right,but don't forget to clean out the air intake at the front of the tower if that gets blocked the fan will not work properly .If you are buying a new power supply ,buy one that is about 50% more power output than you need this will ensure it has an easy life,especially if your tower is in a confined space with poor airflow .

Only thing I'll fix on a power supply unit is the fan, anything else goes and I throw the whole unit away. Just got through fighting a bad unit on my boys, wasn't it's fault, the florescent light went out and took the supply with it. Had weird sympoms though, it wasn't all that obvious.

My point is they are relatively cheap compared to the rest of the computer, and having blown once I assume the rest of the parts aren't too far from failing. I do not get top of the line units, my average unit cost is between $16 to $35, depending on wattage, and their average lifespan is usually well over 3 years.

Sorry for bumping this thread up but I believe it has some relevance to what I need to ask. I've come across a few atx power supplies with bulging capacitors. Since I can't use those psu, how about I take working capacitors from one bad ps and replace bad capacitors on the other? I know I can order new caps, but since I would have to have so many different rated caps, why not just hold on to these power supplies and salvage the working parts for use in other power supplies. I'm also interested in doing the same with motherboard capacitors, but can I use those caps for power supplies and vice versa?

My supply is 4 yrs old, runs for plenty of time and has heavy load including graphics card, Lighting systems and about 4 fans... 2 I added myself.. Its why I guess runs cool... It doens't make much noise but I have to clean it frequently due to heavy air circulation.. But thats no prob.. System has 6 fans totally including cpu..

Over the past couple of months, my home computer has been acting up. During bootup the computer start sequence would fail, right after the drive started to spin up. I found that if I turned off the "hard" on/off switch at the back of the computer (the one that's on the power supply), and turned it back on, I could get the computer to start, and it would run without problems. The problem seemed to me to be a power supply that was failing, so I figured that I would need to replace it shortly.

The first time I noticed any problems was when I tried to restart the computer after it had been put in stand-by mode, so I stopped using stand-by and would shut it down instead. Recently, I have started noticing the problem during bootup.

Yesterday morning, I was unable to get the computer to start up, even after three or four attempts using the trick that had worked before. On the way to work I bought a new power supply, and when I got home, installed it. The computer now seems to be working as it should. This leads me to believe that the old power supply actually was the culprit.

I should add that the computer is about two years old, and is one that I put together from parts purchased at a chain computer/electronics store (Fry's). The old power supply was 350 W, which I believe was sufficient for the machine. The new one is 500 W (the place I got it had only one model).

My question is: What would have caused my old power supply to fail after what seems a relatively short time (about two years). The MTBF for the new one is 50,000 hours, which at the rate my wife and I use this computer should last us 50 to 100 years. I don't know anything about the internals of a power supply. What are the parts that can fail?
Thanks,
Mark

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Thats a good thing you did by purchasing more wattage SMPS. now look for any malfunctions in your computer components. if you are using AMD proceessor then your cooling requirement is more and you need to add an additional fan in the cabinet. dont keep the cabinet open. many problems arise due to dust and moisture. try not to keep computer in sleep/standby mode since it keeps everything working. shut it down or hibernate it. blow dust off the cabinet every 6 months. a 500 watt supply will work fine for you.

Thats a good thing you did by purchasing more wattage SMPS. now look for any malfunctions in your computer components. if you are using AMD proceessor then your cooling requirement is more and you need to add an additional fan in the cabinet. dont keep the cabinet open. many problems arise due to dust and moisture. try not to keep computer in sleep/standby mode since it keeps everything working. shut it down or hibernate it. blow dust off the cabinet every 6 months. a 500 watt supply will work fine for you.

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Hey rohit...
Mind checking which millennium you are in......

Why do you guys tend to post away without even checking the thread date....

I've had one that was plugged into a UPS die, which I promptly replaced. The replacement then blew after a day or two. After that, I decided to get my Dad (who's an electrician) see what was up with it. We then determined that the UPS wasn't provided proper sine-wave AC, it was a really weird wave form. This must've really upset the caps inside the PSU. I suppose it's the same sort of thing if you have a mains voltage dip or flutter, except constantly.

So after setting the PC up with a new PSU and a new UPS, that was one very expensive lesson learned. Cheap UPS = stay away.